GM's chief sales analyst, Paul Ballew, last week said the automaker would be more aggressive on incentive spending over the remainder of the year, in response to heavy discounts from competitors, especially on pickup trucks.

"We're going to be very responsible with what we do and get the right balance between selling at a profit versus really watching share decline," Lutz said on Thursday.

The market for pickup trucks, which accounts for nearly 13 percent of overall U.S. sales, has become the most fiercely competitive segment as automakers sacrifice margins with expensive sales offers in order to protect market share.